code: def pytest_configure(config):
      config.addinivalue_line(
          "markers", "slow: mark test as slow to run"
      )
      backend = config.getoption("--backend")
      if backend is None:
          backend = os.environ.get("NETWORKX_TEST_BACKEND")
      if backend:
          networkx.utils.backends._dispatchable._automatic_backends = [
              backend
          ]
          fallback_to_nx = config.getoption("--fallback-to-nx")
          if not fallback_to_nx:
              fallback_to_nx = os.environ.get("NETWORKX_FALLBACK_TO_NX")
          networkx.utils.backends._dispatchable._fallback_to_nx = bool(
              fallback_to_nx
          )
      # nx-loopback backend is only available when testing
      backends = entry_points(
          name="nx-loopback", group="networkx.backends"
      )
      if backends:
          networkx.utils.backends.backends["nx-loopback"] = next(
              iter(backends)
          )
      else:
          warnings.warn(
              "\n\n             WARNING: Mixed NetworkX configuration! \n\n"
              "        This environment has mixed configuration for networkx.\n"
              "        The test object nx-loopback is not configured correctly.\n"
              "        You should not be seeing this message.\n"
              "        Try `pip install -e .`, or change your PYTHONPATH\n"
              "        Make sure python finds the networkx repo you are testing\n\n"
          )
  
file_path: networkx/networkx/conftest.py
imports: import os
  import sys
  import warnings
  from importlib.metadata import entry_points
  import pytest
  import networkx
label_desc: Use image node_id 2 for calling a global function with example usage: pytest_configure(config) without return types